1. Field of the Invention
The present invention relates to an imaging device, and to a control method for an imaging device.
2. Description of the Related Art
Depth of field of a taken image varies depending on optical characteristics such as aperture value and focal length. When shooting in sports mode using a telephoto lens, a deep depth of field is preferred. When taking a portrait photograph, however, bokeh, or blurring, is used in a way that is pleasing to the eye. With a 135 film camera (35 mm silver halide film camera), it is possible to sufficiently vary the depth of field by appropriately selecting aperture value and focal length. However, with digital cameras, which have become widespread in recent years, the depth of field becomes deep due to the surface area of the imaging section being small, and even when shooting with the same angle of view as with a film camera prominent background bokeh is not achieved. There have therefore been various proposals for bokeh processing to generate an image that has a shallow depth of field using image processing, to give a taken image that appears as the photographer intended.
For example, Japanese patent laid-open No. 2004-310504 (laid-open Nov. 4, 2004) proposes a method of generating an image having a shallow depth of field from two images taken with different aperture values. Also, Japanese patent laid-open No. 2005-229198 (laid-open Aug. 25, 2005) proposes a bokeh processing method that gives a background of a shallow depth of field by separating image data of a subject region and image data of a background region from a master image, and subjecting the image data of the separated background to bokeh processing, and then combining the background image data after bokeh processing with the master image data. Further, Japanese patent laid-open No. 2009-177782 (laid-open Aug. 6, 2009) proposes bokeh processing for blurring a background by changing an image combining ratio for a master image and a blurred image, based on amount of variation in a high frequency component of two images each having different aperture values.